F# to Join VB and C# in Microsoft Language Stable

Microsoft will deliver a new general-purpose language known as F# to developers next year. F# supports financial modeling and analysis, scientific data analysis, algorithms and academic computing. F# is a functional programming language for .NET.

NEW YORK-Microsoft
plans to deliver a new general-purpose programming language to developers,
known as F#
(pronounced F Sharp), that takes advantage of the functional programming
model.
Speaking at the VSLive New York conference here on Sept. 8, Luke Hoban, the
F# program manager at Microsoft, said F# is a functional programming language
for .NET, which will join C# and Visual Basic
as core .NET languages.

Functional programming is a programming paradigm that treats computation as
the evaluation of mathematical functions and avoids state and mutable data. It
emphasizes the application of functions, in contrast with the imperative
programming style that emphasizes changes in state.

"Functional programming means functions are very important," Hoban
said. "With F# we pass around functions like any kind of data."
Hoban further explained that "F# is a functional, object-oriented,
imperative and explorative programming language for .NET."
And, "F# makes an inference that a language should be good at doing explorative
development," he said.
However, "by no means is F# a replacement for C# or Visual Basic, which
are great for mainstream development," Hoban said. "F# is meant to go
out and extend the reach of .NET to new
developers and new types of developers."

F# started as a research project in Microsoft's research lab in Cambridge,
England. "And about
eight months ago Microsoft decided there was an audience we could target more
aggressively" with the language, Hoban said.
Although Hoban described F# as a general-purpose language, he said it is
particularly suited to doing technical algorithms and explorative tests,
financial modeling and analysis, data mining, scientific data analysis, domain
specific modeling, and academic uses. In fact, Hoban said many of the early
adopters of F# are financial services companies in New
York on Wall Street.
Hogan also noted that F# borrows from other languages and is strongly typed,
has a succinct syntax, is scalable, has libraries, and is explorative,
interoperable and efficient. Other characteristics early users have listed as
benefits of F# are that it is quick coding, supports scripting, has good
performance, is symbolic and has .NET
integration.
At the end of August, Microsoft released the September CTP (Community
Technology Preview) of F#. That CTP features improved integration with Visual
Studio 2008 and was co-developed by Microsoft Research in Cambridge
and Hoban's group in Redmond, Wash.
The September CTP of F# also features improvements to the F# language and
libraries to make them simpler and more regular. And there is also a new
language feature, Units of Measure, which extends F#'s inference and strong
typing to floating-point data.
Don
Syme, the Microsoft researcher who devised F#, in a blog post, said:

"F# is a simple, type-safe, efficient, scalable language for the .NET
platform that supports both functional and object-oriented programming. One of
the key things about F# is that it spans the spectrum from interactive,
explorative scripting to component and large-scale software development. In
this release we've made major improvements to the language, libraries and tools
across this spectrum."

Along with the CTP, Microsoft also launched "a new F# Developer
Center on MSDN [Microsoft Developer
Network]," said S.
"Soma" Somasegar, senior vice president of Microsoft's Developer
Division, in a blog post. "This developer center provides resources
for F# developers and links to F# user communities."
Hoban said Microsoft will deliver in 2009 the first supported release of F#
that will be aligned with the next version of Visual Studio. However, Hoban
said it is not yet clear whether F# will be delivered as an add-in or "out
of the box."
Because F# supports immutability, it is good for parallel programming, Hoban
said. "We treat things as being immutable, and immutability comes up when
we get to more parallel applications. ... What immutability means for F# is if
you define a value you can't change it-it's not mutable."
F# has "the static typing of C# with the succinctness of a scripting
language," Hoban said. The language also features a type inference
capability, where the compiler can tell what type the developer intended to use.
Indeed, Hoban demonstrated the integration of F# with Visual Studio, where he
hovered the cursor over a piece of code and a pop-up displayed what type the
code was. "On the language side, some of the consistent feedback we get
about F# is that the combination of type-inferred programming and interactive
exploration allows you to develop correct algorithms and objects quickly and
with a very low error rate," Syme said.
F# also supports pattern matching, functional collections and scripting via
the Script.fsx extension, said Hoban said, who showed a demonstration in which he
used DirectX and F# to do visualization of data.
Regarding performance, "in F# you get really good performance,"
Hoban said. "F# can probably run 10 to 20 times faster than Python. ...
You should look for performance at about the same level as C#."
Moreover, Hoban said as proof of the applicability of F#, "we develop
F# in F#," with only one or two side projects in C#, Visual Basic and C++
contributing to the development of the language.

Darryl K. Taft covers the development tools and developer-related issues beat from his office in Baltimore. He has more than 10 years of experience in the business and is always looking for the next scoop. Taft is a member of the Association for Computing Machinery (ACM) and was named 'one of the most active middleware reporters in the world' by The Middleware Co. He also has his own card in the 'Who's Who in Enterprise Java' deck.